Résumé
We measured dynamic modulus of elasticity (Ed) and bending strength (?) for several tree species growing in or around an avalanche path in the French Alps. Species were single- or multi-stemmed, the latter being more abundant at the centre or edges of the path. #Alnus viridis#, generally found at the centre of avalanche paths, had the lowest Ed and ?, and was strongly multi-stemmed, thus allowing this species to bend during an avalanche or to resprout if damaged. In several species where stem bases were procumbent after snow damage, Ed increased with height up the stem, conferring a mechanical advantage on these young stems which need to grow quickly upwards and dominate the canopy. Ed did not change along stems in #Corylus avellana#, a multi-stemmed shrub with stems often leaning on each other, thus providing mutual support, as also found in semi self-supporting plants. (Résumé d'auteur)